1. Field
The present general inventive concept relates to a method of manufacturing a light emitting device (LED) package, and more particularly, to a method of manufacturing an LED package that may include forming a reflector to increase an intensity of light emitted from an LED thereof.
2. Description of the Related Art
A light emitting device (LED) is a semi-conductor light emitting apparatus that emits light when a current flows. The LED may have features of a long life-span, a low power consumption, a fast response speed, an excellent initial operation, and the like and thus, may be widely applied to a lighting device, a headlight and a courtesy light of a car, an electronic display board, a backlight of a display device, and the like. The number of fields that adapt the LED has increased.
Recently, the LED is used as a light source of various colors. As the demand for a high power and high luminance LED, such as a white LED for lighting and the like, increases, research for improving the performance and reliability of an LED package has been actively conducted. To improve the performance of an LED product, an LED package that effectively extracts light, that has an excellent color purity, and that has a uniform property among products may be needed in addition to an LED with an excellent optical efficiency.
Phosphors may be disposed on a blue LED or an ultraviolet LED to obtain a white light using the LED. The white LED may color-transform a portion of light extracted from the blue LED or the ultraviolet LED, based on a combination of a red phosphor, a green phosphor, a blue phosphor, and a yellow phosphor, and may provide a white light by mixing the phosphors. A light extraction efficiency may correspond to the most important factor for determining the performance of the white LED.
A reflector may be used in an LED package structure to increase an intensity of light by increasing an extraction efficiency of light emitted from an LED chip. Also, an angle of a reflector cup may have a great effect on the intensity of light. When the angle of the reflector cup is small, the intensity of light extracted may be relatively low since an angle of reflection is small, and the light may fail to be emitted to an external environment, as a result of total internal reflection. Conversely, when the angle of the reflector cup is set to be great, the intensity of light extracted may increase since the angle of reflection increases.
An LED package formed using a currently available injection molding has a problem in that a size of the LED package increases when an angle of a reflector cup increases. In an LED package structure, a scattering path increases while light, generated by a blue LED, is being converted by a phosphor and thus, conformal coating for applying a phosphor of a predetermined thickness on an LED chip may be used to increase an intensity of light.
However, an LED chip formed using the conformal coating generally has a structure without a reflector. In a case of a structure including the reflector, the LED chip may be mounted to a pre-mold reflector package of a cup shape, formed using the conventional injection molding. In this instance, a phosphor layer may be formed using a method of covering the LED chip by injecting a phosphor material using a dispensing process.
When the reflector is formed in the aforementioned manner, a rate of increase in the intensity of light varies depending on the angle of the reflector cup. When a size of an LED chip is constant, the angle of the reflector cup may increase, in doing so a size of the LED package may increase as well. Also, a scattering path may increase unnecessarily while the light generated by the LED chip is being converted by a phosphor. Accordingly, a rate of increase in the intensity of light may decrease.
Nanoimprint lithography refers to a method of transferring a shape of a minute pattern by pressing a resin material applied onto a substrate with a mold in which the minute pattern is carved through electron beam exposure or etching technologies. Here, the mold is also referred to as a stamp or a template. For example, when nanoimprinting is performed using thermoplastic, a minute pattern may be transferred by pressing, with a mold, a resin that may be softened by heating the resin to a temperature over a glass transition temperature.
The nanoimprint lithography corresponds to a technology for manufacturing a nanoscale structure at a low cost, and is regarded as a replacement for unproductive electron beam lithography or expensive optical lithography.